Modelling the respiration rate of fresh-cut Annurca apples to develop modified atmosphere packaging

In this work, the effect of temperature, oxygen, red coloration process and post-harvest storage time on the respiration rate of fresh-cut Annurca apples was studied to properly develop modified atmosphere packaging. Our results showed that the red coloration process and the post-harvest storage time did not affect the respiration rate or the respiratory quotient of fresh-cut Annurca apples in the range of temperature studied (5–20 °C). A Michaelis–Menten-type equation, with the model constants described by means of an Arrhenius-type relationship, was used for predicting respiration rate on varying the temperature and O₂ concentration in the head space. The maximal respiration rate (mL kg h⁻¹) (RR_max) and the O₂% corresponding to     values estimated at the reference temperature (12.5 °C), i.e. the average of the experimental temperature ranges, were, respectively, 6.77 ± 0.1 mL kg⁻¹ h⁻¹ and 0.68 ± 0.07% v/v, and the activation energy of the aerobic respiration rate of fresh-cut Annurca apples was estimated at 51 ± 1 kJ mol⁻¹. The model works well to develop a modified atmosphere for fresh-cut Annurca apples.     

Modelling the respiration rate of minimally processed broccoli (Brassica rapa var. sylvestris) for modified atmosphere package design

In this work, the effect of temperature, oxygen and carbon dioxide on the respiration rate of minimally processed broccoli was studied to develop suitable modified atmosphere packaging. Respiration rate was measured at 3, 5, 7, 10, 15 and 20 °C under different gas compositions of O₂ and CO₂ (1%, 5%, 10%, 15% and 21% of O₂ with the balance N₂, a mixture of 10% and 20% of carbon dioxide with the balance air and a mixture at 3% of O₂ and 15% of CO₂ with the balance N₂). As expected, temperature was the most influential factor on respiration rate, for all atmospheres tested: increasing the temperature from 3 to 20 °C resulted, for air‐stored samples, in a 84% change in oxygen respiration rate, whereas at constant temperature, the respiration rate decreased by 35% with lowering the O₂ concentration from 21% to 1% and by 44% with increasing the CO₂ concentration from 0% to 20%. The Michaelis and Menten competitive model with maximum respiration rate varying against temperature with an Arrhenius equation accurately described the influence of gas composition and temperature on the respiration rate of minimally processed broccoli, and it was used to design a suitable package.     

硅窗气调包装保鲜贮藏茶树菇呼吸特性与贮藏品质的研究

以乙醇作为厌氧呼吸的指标，评估气调包装贮藏茶树菇时厌氧呼吸产生的条件，探讨硅窗对茶树菇的呼吸特性与贮藏品质变化的影响。结果表明：与普通气调相比较，硅窗气调能明显改善茶树菇贮藏的气体环境。贮藏温度为3℃，硅窗面积0．9cm。以上和贮藏温度为7℃，硅窗面积1．2cm。以上，都能避免厌氧呼吸的发生，茶树菇有更好的贮藏品质。     

Evaluation of parameters affecting modified atmosphere packaging engineering design for pomegranate arils

This study evaluated the effects of passive modified atmosphere packaging design parameters as a function of the amount of product (g), temperature (°C) and time (days) on two pomegranate cultivars. Arils (75, 100 and 125 g) were packed in trays, heat sealed with polylid film and stored at 5, 10 and 15 °C for 14 days, and analysed for physicochemical parameters viz headspace gas composition, weight loss, total soluble solids, titratable acidity, pH, anthocyanin, aerobic‐mesophilic bacterial and fungal load (log CFU g^?1). At the highest temperature and weight, O₂ concentration continuously decreased below the critical limit (2%) after 4 days, while at 5 °C, this lower limit was not reached. Shelf life of arils was limited to 10, 7 and 3 days by fungal growth ≥2 log CFU g^?1 at 5, 10 and 15 °C, respectively. Using unsteady‐state equation, a good agreement was found between simulated and experimental gas composition data.     

果蔬自发气调包装中呼吸速率研究进展

气调包装(modified atmosphere packaging,MAP)可以有效延长果蔬保鲜期,减少果蔬储运过程中腐败变质造成的巨大经济损失.其中自发气调包装利用果蔬自身的呼吸作用和包装薄膜选择透过性,建立适宜果蔬保存的气体环境,降低果蔬的生理消耗,对延长保鲜期有明显功效.自发气调包装关键技术是果蔬呼吸速率和包装...     

高氧气调包装对鲜切胡萝卜的保鲜效果

研究了不同氧分压条件对鲜切胡萝卜保鲜效果的影响,评定其在贮藏过程中感官品质、呼吸强度、PPO、POD、PAL活性的变化。结果表明,40%氧气包装不适合鲜切胡萝卜贮藏保鲜。100%氧气包装的保鲜效果最好,可有效抑制鲜切胡萝卜呼吸强度以及PPO、POD、PAL的活性。60%、80%氧气包装的保鲜效果次之,但均可起到保鲜的作用。      

Ethylene production,respiration and gas exchange modelling in modified atmosphere packaging for banana fruits

A mathematical model was developed from experimental measurements to describe the evolution of the O₂, CO₂ and ethylene in a modified atmosphere packaging system for Cavendish bananas. The respiration and ethylene production in the fruits were experimentally obtained from a closed system method and then represented by Michaelis–Menten equations of enzyme kinetics. The gas transfer through the packaging was described by a Fick's diffusion equation, and the temperature dependence was represented based on the Arrhenius law. The model was validated by packaging the fruit in perforated bags of polypropylene and low density polyethylene at 12 °C for a period of 8 days. With the developed model it was possible to satisfactorily describe the experimental evolution of the gas content in the headspace of the packages, obtaining coefficients of determination (R²) of 0.93 for the O₂ levels, 0.90–0.91 for the CO₂ levels, and 0.89–0.93 for the ethylene levels.     

Modelling the gas exchange rate in perforation-mediated modified atmosphere packaging: Effect of the external air movement and tube dimensions

Perforation-mediated modified atmosphere packages control the gas exchange rate and thus the internal atmosphere composition by judicious choice of dimensions of small tubes in perforations in an otherwise hermetic container. The aims of this work were (i) to study the effect of external turbulence on the gas exchange rate through small perforations, (ii) to develop a mathematical model to predict the effect of tube dimensions and hydrodynamic conditions on gas exchange coefficients, and (iii) validate the model developed during the storage of shredded carrots. Different hydrodynamic conditions in the controlled temperature room due to the storage temperature settings (5, 10 and 15 °C) and PVC tubes dimensions (diameter from 1.5 to 4.5 mm length from 2.0 to 6.0 mm) were tested. Results showed that, as expected, hydrodynamic conditions (induced turbulence) and tube diameter had a significantly positive effect on the mass transfer values, whereas tube length had a negative effect. The permeability ratio between CO₂ and O₂ was 0.83 ± 0.01 and did not show any pattern with the factors tested. The gas exchange coefficients increased with decreasing temperature, as the establishment of lower temperatures implied a frequent air movement. A mathematical model to estimate changes of gas composition over time as a function of tube dimensions and hydrodynamic conditions was developed and found to have good predictive abilities. The model was validated during the storage of shredded carrots at 5 °C in PM-MAP, showing a good agreement between the experimental and predicted gas exchange of O₂ and CO₂. The results obtained in this work showed that hydrodynamic conditions of the cold storage room affected the gas exchange rate in PM-MAP.     

The effect of harvest date on the responses of Discovery apples to modified atmosphere retail packaging

In order to study effects of physiological maturity on responses of Discovery apples to modified atmosphere (MA) retail packaging, samples of fruit were picked at 3–4 day intervals over a 3-week period spanning the development of the climacteric rise in respiration and the normal marketing season for the variety. The apples were packed in MA (301∼.ethylene vinyl acetate) or perforated control packs and held under simulated marketing conditions at 10 or 20°C. The degree of modification of the pack atmospheres and the effects of MA packaging on fruit ripening changes were influenced by harvest date and related to the respiration rate of fruit when packed. MA packs were effective in retarding softening and skin colour changes in immediately pre-climacteric and early climacteric fruit. There was little risk of taint development, except during 14-day simulated marketing periods at 20°C. Little beneficial effect of MA packaging was found in apples harvested 4 days before the onset of the climacteric; relatively little deterioration occurred in such fruit in perforated control packs. Beneficial effects of MA packaging on ripening changes and quality attributes were reduced, and taint risk enhanced, when the technique was used for late picked fruit with much higher rates of respiration. Possible causes for the observed relationship between the different stages of physiological maturity of Discovery apples and their responses to MA packaging are discussed.     

蒲菜气调保鲜贮藏技术研究

研究气调包装对贮藏过程中的蒲菜的营养成分(Vc、粗纤维、总酸、总糖等)的含量变化及外观变化的影响,提出适合蒲菜气调保鲜的包装材料和气体配比。结果表明:气体比例为5%O2∶10%CO2∶85%N2,选用T5保鲜袋,在低温下可保鲜3周,可比对照组延长保鲜期1周。     

The performance of several oxygen scavengers in varying oxygen environments at refrigerated temperatures: implications for low-oxygen modified atmosphere packaging of meat

The oxygen scavenging capacity of four commercially available iron-based oxygen scavengers was studied. Individual oxygen scavenger sachets were placed in pouches and filled with 1%, 2%, 6%, 12% or 22% oxygen, 40% carbon dioxide and balance nitrogen, and stored at 3 °C or 10 °C, with or without a drip pad infused with water and monitored over 24 h. The four scavengers all reduced oxygen from the packs at the oxygen concentrations and temperatures tested. However, for all of the conditions measured, the scavengers did not absorb their nominal capacity in the 24-h period. In anoxic modified atmosphere packaging of beef steaks, it is essential to reduce residual oxygen levels to below 0.05% as quickly as possible to minimise the formation of metmyoglobin. While the scavengers tested were effective in removing oxygen, the rate of removal would appear not to be fast enough to create the anoxic conditions required to prevent metmyoglobin formation in beef steaks, particularly in those cuts, which are highly susceptible to metmyoglobin formation. Reproducibility was also a critical issue for the scavengers, particularly at low oxygen concentrations. None of the scavengers had a coefficient of variation of less than 20% at the low oxygen concentrations. Therefore, to obtain consistent results, it is recommended that multiple scavengers be used.     

基于单纯形-重心设计优化气调包装冷鲜猪肉的气体比例

为优化冷鲜猪肉气调包装的气体比例,增强其保鲜效果,以菌落总数、挥发性盐基氮（TVB-N）值、p H和感官品质为指标,基于单纯形-重心设计考察O₂、CO₂和N₂的不同配比对冷鲜猪肉的品质维持作用。通过与托盘包装的对照组比较发现,适宜的气体配比能有效抑制冷鲜猪肉中微生物的生长、减少TVB-N的生成、保持产品的感官品质,且各指标两两之间均存在极显著的相关性（p<0.01）。以三种气体各自所占体积百分比为因素,筛选产品贮藏至第8 d和第10 d的菌落总数、TVB-N值及二者加权值为响应值,建立6套回归模型并分别优化得到6组气体配比方案。通过验证确定冷鲜猪肉气调保鲜的最佳气体比例为22%O₂和78%CO₂,在此条件下贮藏至第8 d的菌落总数和TVB-N值分别为5.85 lg（cfu/g）和14.00 mg/100 g,相比对照组可延长产品货架期达5 d。      

自发气调对鸭梨果实生理生化品质的影响

以鸭梨为试材,研究了自发气调贮藏(MAP)对果实采后生理品质的影响。结果表明,MAP贮藏增加了鸭梨果实贮藏期间的黑心病发生率,贮藏结束时,MAP贮藏果实的黑心指数较对照提高了78%。MAP贮藏增加了果实多酚氧化酶的活性,减少了总酚的含量。MAP贮藏还抑制了果实内过氧化氢酶和抗坏血酸过氧化物酶的活性,MAP贮藏果实较对照果实具有较高的丙二醛和过氧化氢含量。      

Innovative processes and technologies for modified atmosphere packaging of fresh and fresh-cut fruits and vegetables

Modified atmosphere packaging (MAP) technology has been commercially viable since the 1970s. Currently, MAP is extensively used worldwide to preserve the quality and extend the shelf-life of whole fresh fruits and vegetables, but is also increasingly used to extend the shelf-life of minimally processed fresh fruit and vegetables. This review discusses new processes and technologies that can be used to improve quality preservation and consumer acceptability of minimally processed produce where high respiration rates and challenging degradation processes operate. New packaging innovations are enabling producers and retailers to further maintain quality for longer. Innovative approaches to extend shelf-life include active MAP with differentially permeable films, films that incorporate antimicrobial properties, edible coatings that confer barriers properties, and the use of non-traditional gases to modify respiration. Intelligent packaging using integrated sensor technologies that can indicate maturity, ripeness, respiration rate and spoilage are also appearing. This review demonstrates that preservation technologies and associated packaging developments that can be combined with modified atmosphere are constantly evolving technology platforms. Adoption of combinations of technology improvements will be critical in responding to commercial trends towards more minimally processed fresh-cut and ready-to-eat fruit and vegetable products, which require specialized packaging solutions.     

Effect of white grape extract and modified atmosphere packaging on lipid and protein oxidation in chill stored beef patties

The oxidative stability of beef patties added 500 ppm white grape extract (WGE), packed in four different modified atmospheres (MAP) with varying oxygen and carbon dioxide levels (70% or 0% O₂, 30% or 0% CO₂, balanced with N₂ in all four combinations) and stored for up to 9 days (4 °C) was evaluated by a sensory panel, formation of TBARS, formation of protein carbonyl, appearance of myosin cross-links, and thiol loss. Formation of secondary lipid oxidation products, as detected by TBARS, and the rancidity, as perceived by sensory analysis, were inhibited in WGE beef patties independent of MAP compared to control beef patties. The protein carbonyl formation was also reduced in WGE beef patties, but no significant effects were observed in relation to different MAP. Loss of thiol groups in control beef patties was consistent with the formation of myosin cross-linkages. In the presence of WGE, thiol groups decreased faster but showed less myosin cross-link formation compared to control beef patties, indicating that WGE interacts with the thiol groups of the myofibrillar proteins, and thus reduces the cross-link formation in beef patties stored in high-oxygen MA.     

Engineering packaging design accounting for transpiration rate: Model development and validation with strawberries

Integrative mathematical modelling for Modified Atmosphere Packaging (MAP) has been used to determine the gas composition inside a package, but can also be used to determine the packaging needs of fresh produce in terms of permeability to gases and water vapour. Transpiration rate (TR) is an important physiological process that influences relative humidity (RH) and condensation inside the package, and ultimately quality and shelf life. Strawberries are an extremely valuable crop, but they are susceptible to grey mould rot, fungal decay, moisture loss and condensation. Quantification of strawberry transpiration rate TR would be required to estimate the packaging material water vapour transmission rate (WVTR) and therefore optimise engineering packaging design. This study investigated (i) the impact of temperature and RH on strawberry TR, (ii) developed a predictive model for quantifying TR, (iii) integrated transpiration rate model into the engineering packaging design and quantified the target WVTR for packaging of strawberry and (iv) validated packaging design by comparison to commercial packaging. Experiments were conducted following an experimental design, considering two factors at three levels (3²), i.e. temperature (5, 10 and 15 °C) and RH (76%, 86% and 96%); TR was recorded during 5 days of storage. The results showed that both RH and temperature had a significant effect on TR. In a given temperature and RH range of study, it varied from 0.24 to 1.16 g/kg h. Mathematical model developed considering the effect of temperature and RH, was further validated at 12 °C and 76% RH, showing very good predictability (R² > 0.997). The TR model was found to be useful for describing the strawberry packaging requisites and for optimal engineering packaging design for strawberry. The target WVTR for achieving optimal RH of 90% at 5 °C was found to be 162 g/m² day. Packaging design validation showed that the package designed considering both gas and water vapour requisites of strawberry yielded favourable results for maintaining quality and shelf life of product.     

含CO气调包装对冷却肉肉色的影响

以宰后冷却24h的猪背最长肌为材料,用四组含不同浓度CO的混合气体进行气调包装,于4±1℃下贮藏,分别在第0、5、1O、15、20天测定相关指标。结果表明：CO气调包装能明显改善肉色,并使冷却内在贮藏期中保持稳定的鲜红色。与无氧组相比,CO和O2的共同存在可以使冷却肉肉色更加自然。     

Responses of CA-stored Bramley's Seedling and Cox's Orange Pippin apples to modified atmosphere retail packaging

The responses of Bramleys and Coxs apples to modified atmosphere (MA) retail packaging were studied in samples of fruit removed from controlled-atmosphere (CA) storage at monthly intervals through the marketing season, packed in MA or perforated control packs and held under simulated marketing conditions at 15C. The degree of modification of the pack atmospheres and the effects of MA packaging on fruit ripening changes were influenced by the duration and conditions of storage prior to packing. In addition, differential effects of MA packaging on the extent of retardation of flesh softening and skin yellowing were found as the storage period was extended. During 2 or 4 weeks at 15C, however, MA packs made from low density polyethylene (LDPE, 30 p) were effective in retarding changes in firmness and skin colour of Bramleys, previously stored for < 22 weeks (October-March) in 8% C02+ 13% O2 or for < 30 weeks (October-May) in 6% C02+3% 02. Similarly, during a 2-week marketing period at 15C, LDPE or ethylenevinylacetate (EVA, 30 II.) MA packs were effective in retarding some ripening changes in Coxs previously stored for < 31 weeks (Oc- tober-May) in < 1% C02+1.25% 02. The practical benefits of MA retail packaging for the marketing of apples are also discussed.     

臭氧水处理结合气调包装对鲜切生菜保鲜效果的影响

研究臭氧水处理结合气调包装对鲜切生菜在4℃贮藏下的保鲜效果。结果表明,臭氧水处理结合气调包装相比于对照组可以有效抑制鲜切生菜组织中细菌的生长繁殖、水分的流失、叶的降解以及多酚氧化酶的活性,降低鲜切生菜腐败、萎蔫、黄化、褐变的速度,维持鲜切生菜的感官品质,同时也有效抑制了鲜切生菜中VC的氧化分解,延长了货架期,使鲜切生菜在贮藏第14天仍具商品价值。另外,研究结果显示在适当低浓度(5%~10%)的O2和CO2比例范围内,经过长时间(6d以上)贮藏后,不同的气调比例对鲜切生菜品质没有显著的影响。     

Volatile organic compound permeation through porous polymeric films for modified atmosphere packaging of foods

The use of perforated packaging films is increasing with the application of modified atmosphere packaging (MAP) to fresh produce. These films provide high to very high mass exchange rates which usefully allow oxygen ingress and carbon dioxide exit. However, the use of porous films also increases the loss of other food volatile components through similar processes. In this paper we present data on the permeation through porous films of several organic compounds found in many fruits and vegetables. The results are compared with those predicted by theoretical equations describing pore permeation processes. A discussion on the significance of these very high permeation values for product quality is also presented through the analysis of ethanol concentration evolution during MAP of mandarin segments. It was found that the barrier effectiveness of the fruit cuticle and the elevated partition coefficient of the organic compounds between the fruit (flesh) and the headspace appear to be responsible for the reduced food aroma compound loss. Copyright © 2004 Society of Chemical Industry